Bill Calhoun, Piano Technician : Glossary

Action: Broadly speaking, the action is the mechanical part of the piano containing the hammers, wippens, dampers, keys, pedals, and associated mechanisms. Sometimes the action is thought of as having sections; one can refer to the pedal action, or the keyboard action. In this case, "the action" often means just the part carrying the hammers and wippens, also called the top action. See also upright for a discussion of types of actions in uprights.
Backcheck: The backcheck catches the hammer as it rebounds off the string. This prevents the hammer from bouncing around, and also helps the action recover quickly so the note can be played again.
Bass: The bass end of the piano is the left side, where the lower-pitched notes are. Technically, the bass is the section of the piano whose strings rest on the bass bridge. See also tenor and treble.
Bridge: The bridge connects the strings to the soundboard, allowing the vibrating strings to cause the soundboard to vibrate. The bridge is a long, narrow wooden piece that is glued to the soundboard and built so the strings rest on it with a certain amount of downward pressure, called down-bearing. Each string is held in place with two pins called bridge pins, which provide side-bearing. The bridge may consist of several parts, including a cap, a body, an apron, and a riser or footing. A piano usually has two bridges; a short one for the bass strings, and a long, sinuous one for the treble.
Cabinet Grand: Cabinet grands are big old full uprights. They stand at about shoulder height or more, and usually have ornate cases. Though technically not grands, they have bigger soundboards and longer bass strings than many grands. The earliest examples of tall uprights were grand pianos more-or-less turned up on end, and some did have cabinet drawers built in.
Case: The case, or cabinet, of a piano is the outside shell that holds the piano's workings. It is often made with furniture-quality veneer, and stained, lacquered, and polished. More than just a skin, certain parts of the case are integral to the piano's structure, particularly the rim and bracing of a grand and the posts and back of an upright. The soundboard and keybed, and sometimes the pinblock, are glued into the case. All of the furniture parts of the piano are regarded as part of the case; the legs, lyre, lid, music desk, etc.
Concert Pitch: The standard of pitch is called concert pitch. It is so named because it is the standard used by professional musicians and orchestras. This is an internationally established standard, though this doesn't prevent musicians and orchestra leaders from preferring a different pitch. At present the standard (set by ISO) is to tune the A above middle C to 440 hertz, or cycles per second, hence the term A440. Many old pianos were built when the international standard (set by France) was A435. There is a current fad to tune to A442 or even higher.
Console: A console piano is a small upright, about 40 to 43 inches in height. Technically speaking, a console has a direct-blow action; that is, the end of a key pushes up on the wippen. In addition, parts of a console's action may be shrunk in height, referred to as compressed. See also spinet.
Damper: The damper is a device for suppressing the vibration of a string. In a grand, the dampers sit on top of the strings; you can see them go up and down as you play the piano. In an upright, they sit against the strings below the hammers. The dampers are spring-loaded, and also sometimes weighted. The last 20 notes or so in the treble don't have dampers. The damper consists of a hinged lever, a thick, bendable wire that runs from the lever to a wooden damper head, and specially shaped felts glued to the head. When you depress a key, the damper lifts off just before the hammer hits the string. When you let go of the key, the damper returns, damping the string. In an upright, the damper is lifted off the string by a little metal spoon on the wippen. In a grand, the damper is lifted by the end of the key.
Full Upright: A full or full-sized upright is the tallest of uprights, at least 48 inches in height. See also cabinet grand and studio.
Grand: A grand piano has its strings and soundboard oriented horizontally, parallel to the floor. Grands are categorized according to length, which is measured from the tail to the front of the keybed trim, including any overhang from the lid. There is no uniform system for naming sizes of grands. Little ones are called baby, the biggest (nine feet long or more) are concert grands, and everything else is called all sorts of things; parlor, studio, sitting-room, apartment, professional, etc. Small, medium, and large are sufficient names. The actions are largely the same in all sizes except in the smallest, where the action parts may be reduced in size, or compressed. See also upright and square grand.
Hammer: The hammer is the part of the action that strikes the string, causing it to vibrate. It swivels on a hinge, and is propelled by the jack. The hammerhead is what actually contacts the string. It is made of very dense felt which has been hydraulically pressed and glued and sometimes stapled onto a central wooden molding. The hammerhead is attached to a long stick called the shank. On a grand action, the other end of the shank has a felt-and-leather-covered knuckle which the jack pushes against. On an upright action, the jack pushes against a felt-and-leather-lined notch in a wooden piece called the butt. The shank fits into the butt, as does the catcher, which is where the hammer is caught by the backcheck.
Jack: The jack is the little wooden lever that propels the hammer. It is attached to the wippen. When the key is depressed, pushing up the wippen, it is the end of the jack that is in contact with the hammer, sending it toward the string. The jack must get out of the hammer's way, however, just before the hammer hits the string. Otherwise it will interfere with the hammer's rebound, which will interfere with the vibration of the string, perhaps blocking vibration altogether. To accomplish this escapement, the jack is hinged. At the crucial moment, its tail contacts an adjustable button, and the jack swings out of the way, an event called let-off. After the hammer rebounds, the jack returns quickly thanks to a spring, and is ready to propel the hammer again.
Key: The key is what you depress to make sound on a piano. It is a wooden lever that is held in place with two pins; one at the fulcrum and another underneath the key at the point where you depress it. The white keys have keytops made of ivory or walrus or plastic, and the black parts of the black keys, called sharps, are made of ebony or stained wood or plastic. The far end of the key, which you normally don't see, has an adjustable piece that pushes or pulls up on the wippen. In grands, the end of the key also holds the backcheck.
Keyboard: The keyboard is the entire collection of 88 keys laid out on a keyframe. The keyboard is secured to the part of the case called the keybed. The keyframe is made up of three rails padded with felt which the keys rest upon. The center rail, called the balance rail, is what the keys pivot on, their fulcrum. Each key is held in place with a pin driven into the balance rail. The back rail is what the back end of the keys rest upon. The front rail is what the front end of the keys land on when you depress them. There are pins in the front rail also, for holding the keys in line. The height of each key is adjusted by inserting paper bushings under the felts on the balance rail. Similar paper bushings adjust how far down each key goes when depressed, a distance called the key dip.
Let-Off: The let-off is an event that occurs during the course of a keystroke. When a key is depressed, it pushes or pulls up on the wippen. The jack, attached to the wippen, pushes on the hammer, propelling it toward the string. The full movement of the hammer is called the hammerstroke. Just before the hammer contacts the string, the jack escapes out from under the hammer by pivoting. It is the escaping of the jack that is the event called let-off. Exactly when in the hammerstroke the jack should escape is determined by an adjustable button.
Lid: The lid is the hinged top of the piano. In a grand, the lid usually has two parts; the flip, which you fold back to expose the music desk, and the main part of the lid. The lid is usually hinged on the bass side, and is held up with a lid prop, often called the stick. Sometimes there are one or two short sticks for holding the lid up at different heights. On an upright, the lid is the very top board that lifts up to reveal the top of the plate, where the tuning pins are. Sometimes it is hinged in the middle and flips back, otherwise it is hinged in back or on the left and lifts up. There is sometimes a small prop for holding the lid up. The lid is often a repository for house plants. If you overwater the plant, the water will drip out onto the lid and damage it. If the lid has a flip, the water will sometimes escape down through the hinge, damaging the interior without your knowing it.
Lyre: On a grand piano, the lyre is the part of the case that connects the pedals to the underside of the piano. It is sometimes fashioned in the shape of a lyre. The pedals and their hinges are held in a pedal box at the bottom of the lyre. The pedal rods are often held in a guide partway up the lyre. The lyre is supported by one or two support rods that resist the sideward pressure of a foot depressing the pedals. Like the grand's legs, the lyre is removable. During a move, the support rods often disappear because they can be so difficult to re-install. Rather than wrestle with them, an unscrupulous mover will figure that the owner won't notice them missing, which is true. Sometimes an upright will have a lyre as well.
Music Desk: Broadly speaking, the music desk is the part of the case that holds up your sheet music. Holding the music properly requires a horizontal surface for the music to sit on and a vertical surface, usually tilted, for the music to lean back against. In a grand, the desk is the horizontal part that usually slides in and out. Attached to the desk is a vertical music rack, sometimes quite decorative, which is hinged, and whose tilt can sometimes be adjusted. There are many music-desk variations on uprights. Frequently the music sits on a horizontal board sometimes called a stretcher, and it may lean on a rack, as on a grand, or it may lean on the front board, which pivots out at an angle to support the music. Sometimes there is a hinged piece that flips down to provide the horizontal surface. The horizontal surface may be padded with felt or leather, or the wood may be ridged, or a small stop might be attached, to keep the music from sliding down. Most music racks on uprights, and some on grands, are poorly designed, and split apart where the hinges are, making repair quite difficult. On uprights they get installed backwards a lot.
Overtones: The rate at which something vibrates is called the frequency, and it is measured in vibrations per second, or cycles per second, or, officially, hertz. A piano string vibrates at many different frequencies at the same time. The lowest frequency is called the fundamental, and all the higher frequencies are called overtones. The fundamental frequency determines the pitch, and the combination of fundamental and overtone frequencies determines the tone.
Pads: Strictly speaking, nothing in a piano is called a pad. Many piano owners, however, will refer to any piece of felt as a pad. More often than not they are referring to either the damper felts or the hammerhead felts.
Pedals: There are generally two or three pedals on a piano, though, on some older instruments, there are more. The right pedal is called the damper pedal, and when you depress it, its pedal action lifts all the dampers off the strings. This effect, when overdone, has led people to call this pedal the loud pedal. When used delicately and precisely, it can achieve wonderful effects. A technique worth learning is half-pedaling; rather than letting the pedal all the way up, let it up just enough to allow the damper felts to brush the strings, rather than damp them completely. This allows you to create and control a very lush sound. Please do not use the pedal to keep time with your foot.

On a grand, the left pedal is called the shift pedal, and it shifts the entire keyboard to one side so the hammers hit two strings instead of the usual three per note. This not only reduces the power, it also affects the tone. This pedal is sometimes called the una corda pedal, which means one string. This name is a historical artifact - due corde, two strings, would be more accurate. Pianists sometimes try to half-pedal the shift pedal. In this case, it ceases acting as a due corde and instead just exposes less worn and compacted parts of the hammerhead to the strings. This does reduce power and change the tone, though the effect is unpredictable, and not recommended.

On an upright, the left pedal is the soft pedal. It moves all the hammers up closer to the strings so there is less momentum to the hammer blow. This also introduces a lot of free play into the keystroke. Some older uprights have a compensating mechanism for taking up this free play. Some grands, especially players, have a soft pedal instead of a shift pedal, and more rarely you may find a shift pedal on an upright.

The middle pedal is a mixed bag, and not all pianos have one. On grands, it is usually a sostenuto pedal. Here's how it works; when you depress a key, it lifts up a damper. If, while holding the key down, you depress this pedal, it will catch that damper and any others that are being held up, and continue holding them aloft while you play other notes. In other words, unlike the damper pedal which lifts all the dampers, this pedal allows you to decide which dampers to lift. If you just depress the pedal without first picking your notes to be held, nothing will happen. On some grands, this pedal is a partial damper pedal, lifting up just the bass dampers. This is a feeble attempt to duplicate sostenuto.

On uprights, the middle pedal is rarely a true sostenuto. It is sometimes another soft pedal, raising the hammers less high than the left pedal. Or it is a partial damper pedal, lifting the bass dampers off the strings. It may be a practice or mute pedal, lowering a strip of felt between the strings and hammers. In this case, the pedal may have a mechanism to keep it held down. Sometimes the strip of felt has a little metal bit for each note, creating a harpsichord or mandolin effect instead of muting. In both these cases, the effect may be activated by a lever elsewhere on the piano, rather than with a pedal.

Occasionally the middle pedal is a spring-loaded decoy, meant for decorative effect.
Piano Technician: Piano technician is not just a fancy name for a piano tuner, there is a difference. A tuner tunes, that's it. A technician is someone who can work with every aspect of the piano. Typically, a technician can tune, repair, regulate, voice, and rebuild. Most technicians have one or two specialties, and technicians will sometimes team up to work on a large project. There is some dispute as to whether a technician must also be a tuner. One of the best piano technicians I know never learned to tune.
Pinblock: A piano string has a certain amount of tension (160 pounds is a typical number), so it must be securely held at both ends. However, one of those ends has to be adjustable. This is done by wrapping the end of the string around a tuning pin, and then driving the pin, like a nail, into a block of wood. The block of wood is called the pinblock. If there is enough friction, the pin will hold the tension. If there is too much friction, the pin will not be adjustable. If there is too little friction, the pin will slip, and not hold the tension. Pinblocks are made from special planks of wood made of many thinner veneers glued and sometimes compressed together. It fits into a special section of the plate, and must be fitted perfectly. In all uprights and many grands, the pinblock is also fitted and glued into the case. This is a crucial piece of wood, and it does wear out eventually, allowing the tuning pins to slip.
Pitch: Sound is a perceptual phenomenon. Our ears receive and detect sound waves, and our nervous system then "interprets" the energy of those waves. Part of that interpretation is experienced by us as sound. If the sound is chaotic, we perceive it as noise. If the sound is orderly in a particular fashion, we perceive it as musical sound. The boundary between noise and music, as any parent will tell you, is not clear, but in the realm where sound is clearly musical, the sound is orderly in that the various frequencies that make up the sound are related in a straightforward mathematical way.

Vibration is measured by its frequency - so many vibrations per second, or, officially, so many hertz. A vibrating piano string is vibrating at several different frequencies at once. Because all these frequencies are orderly in that particular way, we perceive the sound from the string as musical sound. In fact, the frequencies are so orderly that we perceive the sound as a single note, having a particular pitch. Most of this pitch perception is based on the lowest frequency of the sound, called the fundamental, but some of the pitch perception is also based on the other frequencies, called overtones. The higher the fundamental frequency, the higher the pitch. We give pitches names, much as we name colors. Do, re, mi is one set of names, A, B, C is another (see more about these pitches in temperament).

Because perception is partly learned, that is, influenced by one's particular cultural setting, different people will perceive pitch differently. But people from one cultural setting will perceive pitch with remarkable consistency. Some people perceive and remember pitch with great precision, especially in the context of other pitches. Some people seem to perceive pitch with something approaching synesthesia, which allows them to identify pitches rapidly and accurately, even in the absence of other pitches. This may be what perfect pitch means.
Pitch-Raising: The strings of a piano stretch out over time. A piano tuned to concert pitch will not stay at that pitch forever. If re-tuning is delayed, the piano's pitch will drop. The newer the strings the more quickly the pitch will drop. A well-made piano will drop in pitch evenly, staying more-or-less in tune with itself, so the pitch drop may go unnoticed. If enough time passes, the piano can wind up a half-step or even a full-step lower than concert pitch. If, at this point, it is desired to have the piano at concert pitch, one or more pitch-raisings will be necessary. A pitch-raising is a quick and rough tuning meant to just add tension evenly to the strings. The strings will respond to the pitch-raising by immediately stretching. They also sometimes respond by breaking. This is why it is not possible to simply tune the piano right to concert pitch - it just won't stay in tune, or at pitch. The pitch-raising (or multiple pitch-raisings) will actually raise the pitch to a point above concert pitch, so when the strings settle, they will settle at concert pitch. Then the piano can be tuned normally, and with reasonable stability. The pitch-raising and the final tuning can often be done in one sitting. In general, if the pitch is an eighth-step low or more (more than 20 cents - see temperament), it will need a pitch-raising. Sometimes, just a section of the piano needs raising, typically the top half or third of the treble. There is such a thing as pitch-lowering as well.
Plate: The plate is the big 400-pound cast-iron piece in the piano which is usually lacquered a brass or gold color. Its function is to hold the tension of all the strings, which altogether is about 20 tons. The plate is bolted into the case so that it sits parallel to and just above the soundboard. The plate sometimes has other cast-iron pieces bolted to it. It also has various projections, bumps, ridges, inserts, and attachments designed to hold the strings in place and at the correct level. An important attachment is the pinblock. The plate may also support other parts of the piano. Sometimes the plate is called the harp.
Rebuilding: Rebuilding any portion of the piano involves replacing all of the parts in an effort to restore that portion to its original condition (or even improve it). The most frequently replaced parts are the hammers, the various felts and leathers of the action, the keytops and sharps, the strings and tuning pins, and parts of the bridges. Sometimes the pinblock is replaced, but usually only in grands. If all of these replacements are made, and the case, soundboard, and plate refinished, the piano is said to have been fully rebuilt. Anything short of this is a partial rebuilding. The only parts of a piano that are never replaced are the plate, the keyboard, and the main body of the case. If just about everything has been replaced, especially the soundboard, and the case and plate refinished and the case hardware replated, the piano is said to have been remanufactured. There are specialized shops and factories for doing this.
Reconditioning: Reconditioning is a very general name for cleaning, repairing, adjusting, tightening, lubricating, shimming and bolstering, buffing and polishing, ironing, easing, softening, scrubbing, scraping, and reshaping various parts of the piano. The work can be extensive, or limited to a portion of the piano, typically the action. Most of the work makes up for delayed maintenance. Some replacement of parts occurs, but usually only piecemeal, as needed, and not to the extent of rebuilding. Reconditioning is a wonderfully economical way to get your piano back up to snuff, especially when combined with regulation and voicing.
Regulation: The action can be thought of as 88 nearly identical mechanisms side by side. Each individual mechanism is made up of many parts, and these parts must work together in a coordinated way. Some parts bump or push or pull against others, other parts are connected by wires or springs or straps or cord. Each part is positioned just so, using screws, wire, and bits of felt and leather and paper. To regulate a part is to position it correctly, coordinate it with the other parts, and time its motion properly with respect to the other moving parts. Doing this involves measuring, bending wires and springs, turning threaded parts, shimming, even using heat to warp and twist wood. Regulating also means making all these adjustments so that each mechanism feels consistent with its neighbors, so that the touch of the piano is regular.
Soundboard: The soundboard is a large sheet of wood braced with wooden ribs. It is made to vibrate by the vibrations of the strings, and it vibrates just the way a drumhead would. When you listen to a piano, it is largely the soundboard that you are listening to. The bridges are glued to the soundboard, and the soundboard is fitted and glued into the case. The soundboard is fitted under tension so that there is some bowing of the board against the strings. This bow is called the belly or crown. Soundboards shrink as they age, and some boards develop cracks. The cracks are not a problem (except cosmetically), but if the board is separating from the ribs, it needs to be reattached.

The soundboard does not amplify the sound of the strings, as is often asserted. Technically, it is a transducer; it efficiently receives the sound energy from the strings and then efficiently transfers sound energy to the air. Very little energy is transferred directly from the strings to the air, so the piano would be exceedingly quiet without the soundboard.
Spinet: A spinet piano is the smallest upright, about 36 to 40 inches in height. Technically speaking, a spinet has an indirect-blow or drop action; that is, the end of a key pulls up on the wippen. An adjustable wooden or wire sticker descends from the key end to an elbow that attaches to the wippen. Unfortunately, this arrangement requires that the keys be much shorter than in other uprights. There are also hybrid actions, where the key pushes on a separate lever that pulls the wippen up. See also console.
Square Grand: A square grand is a kind of grand piano that is rectangular in shape and sits on four legs rather than the three of traditional wing-shaped grands. The strings, rather than running back toward the tail from the keys, run across the piano, so the square grand is wider than it is deep. This arrangement forces the action into an awkward geometry that can be difficult to adjust and regulate. The square grand is also difficult to repair and tune, so some technicians will have nothing to do with them. They were designed and built as a space-saving alternative to the winged grand, and were very popular in the late nineteenth century. Square grands were eventually supplanted by uprights. Don't be fooled into thinking they are rare or valuable. They are neither, simply old, obsolete, and sometimes quite ornate, but a square grand in good shape can still be a pleasure and a curiosity.
Stretched Octave: Stretched octaves are a natural characteristic of the piano because of the stiffness of the strings. Piano tuners sometimes stretch the octaves further, either deliberately or unknowingly. Past a certain point, octave stretching is just a distortion of the tuning, and can be regarded as improper tuning. Some musicians believe that distorting the tuning is a good way to add "cut" or "presence" to the piano's sound. This is similar to the fad of tuning to A442 (see concert pitch). Correcting the tone of the piano, improving one's tone-control technique, or adjusting the sound reinforcement are all preferable to excess octave stretching. (See also temperament.)
String: The strings of a piano are the long wires that the hammers strike, causing the vibrations that ultimately become the sound of the piano. The strings are made of special high-tensile steel wire sometimes called piano wire. At one end they attach to hitchpins inserted in the plate. At the other end they are coiled around tuning pins inserted in the pinblock. The strings with the highest pitch are also the thinnest, and they become progressively thicker and longer the lower the pitch. At some point the strings cannot be any longer, so they are made thicker by wrapping the wire, usually with a copper winding. These are the wound strings, found in the bass section. The entire layout of the strings, their lengths, diameters, windings, and placement, is called the scale of the piano, and it is the heart of a piano's particular design.
Studio Upright: A studio upright is not quite as tall as a full upright, from 43 to 48 inches in height. It has a direct-blow action; that is, the end of a key pushes up on the wippen. A studio's keys and action parts are always full-sized. Studios are often marketed to schools, and they tend to have plain cases and be ruggedly built. See also full upright and console.
Temperament: If you were to pluck a piano string, it would vibrate at a certain frequency, so many vibrations per second. You would perceive the sound as having a certain pitch. If you were to locate and then pluck the string that vibrates at twice that frequency, you would perceive the pitch as being higher. But you would also sense that both pitches were somehow the same. This particular pitch relationship, between a sound at one frequency and a sound at twice that frequency, is called an octave.

In all systems of music, the octave is divided into several different pitches. In the musical system of Western Europe, where the piano was born, the octave is divided into seven pitches, named the familiar do, re, mi, etc. The octave is further divided into pitches that are sharp and flat these seven pitches. Exactly how many pitches there are in an octave has varied over historical time, but currently we divide the octave into twelve pitches; the familiar seven plus five more that serve as both sharps and flats. Each pitch is regarded as a half-step away from its neighboring pitches.

The piano tuner gets to decide exactly how to split up the octave. Doing so is called setting the temperament. There are many different temperaments, but currently the accepted temperament for a piano is called equal temperament. As the name suggests, in the equal temperament the twelve pitches of the octave are set so they are all equidistant in pitch from each other. Another way of measuring pitch is to divide the octave into 1200 equal parts, called cents. An equal-tempered half-step thus spans a pitch difference of 100 cents.
Tenor: The tenor section of the piano is the middle section, between the bass on the left and the treble on the right. Technically, the tenor is the section of the piano whose strings rest on the lower end of the treble bridge. These strings may be of a different composition than the rest of the treble strings, and may be arranged differently. In older pianos there is sometimes a separate tenor bridge.
Tone: A piano string vibrates at many different frequencies at the same time. The lowest frequency is called the fundamental, and all the higher frequencies are called overtones. The combination of fundamental and overtone frequencies determines the tone of the string's sound. The words used to describe tone have a similar imprecision to the words used to describe taste. The tone of a note can be said to be brittle, bell-like, glassy, bright, harsh, brilliant, sonorous, dark, velvety, nasal, dull, tubby, hollow, zingy, even chocolate-y. Some of the character of a note's tone is inherent to the particular piano. Some aspects of the tone are adjustable, in a process called voicing.

The tone of a note changes during the time that the note is held, is different depending on how hard the note is played, and has qualities that depend on what section of the piano it is in. A keen pianist tries to control tone by manipulating these and other variables; a great piano has a lot of possibility for tone manipulation, as well as beautiful tone overall.
Treble: The treble end of the piano is the right side, where the higher-pitched notes are. Technically, the treble is the section of the piano whose strings rest on the treble bridge. This would include the tenor section, which is usually regarded as part of the treble. See also bass.
Tuning: Tuning is the process of adjusting the pitch of each string. This is done by using a special tool, called a tuning wrench (or tuning hammer), to turn the tuning pin, altering the tension on the string, and thus changing the pitch. The tuner uses a tuning fork or an electronic tone generator to establish the beginning pitch (often concert pitch). Then he (or she) sets the temperament, and then tunes the bass and treble octaves. The notes that have two and three strings are tuned so that the multiple strings are at unison, that is, at the same pitch. Oddly enough, the tuner does not listen to pitch to determine the pitches. He sounds two pitches at once, and listens to the interference pattern that results. This interference pattern, called beats, is the result of the interactions of the various frequencies of the two strings. Some tuners work by ear exclusively, some work using an electronic tuning indicator exclusively, and many work with a combination of both. A good ear still beats a good machine. The tuner is also responsible in part for the stability of the tuning. A careful tuner knows how to set the tuning pin and the string so that they rest securely, without shifting and going out of tune quickly.
Tuning Pin: A tuning pin is a thick, short steel cylinder, with a top specially shaped so a tuning wrench can fit it. A hole is drilled through the pin to allow a string to pass, and then the string is wound around the pin, forming a coil. The tuning pin is driven, like a nail, into the pinblock, usually passing through an opening in the plate. Thus established, the tuning pin can be turned with the tuning wrench to adjust the tension of the string. Tuning pins come in different sizes. When the pinblock begins to wear, losing its grip on the tuning pin, one remedy is to re-pin the string, using a larger tuning pin.
Upright: An upright piano has its strings and soundboard oriented vertically, parallel to the wall. For this reason it is also called a vertical. Uprights are categorized according to height, which is measured from the floor to the top of the lid. The categories are, in descending height, full upright, studio upright, console, and spinet.

Uprights are also distinguished by different types of actions. Most uprights have a direct-blow action, where the end of the key pushes up directly on the wippen. In taller uprights, there will be an intermediate mechanism to connect the key to the wippen above it. This extra mechanism does not appear in consoles, where the key end directly contacts the wippen. In addition, the console action may be a little compressed in height. The spinet has an indirect-blow action, where the end of the key pulls up on a mechanism attached to the wippen below it. This is also called a drop action, because the top action sits below the level of the keys. Some spinets have a hybrid action, where the key end pushes up on a mechanism that pulls up on the wippen, and the action is not dropped quite as far.
Voicing: A piano string vibrates at many different frequencies at the same time. The lowest frequency is called the fundamental, and all the higher frequencies are called overtones. The combination of fundamental and overtone frequencies determines the tone of the string's sound. The mix of frequencies, or spectrum, of any given note is determined by quite a few variables, some which the technician can control, some not. The primary variables which the technician can control are various attributes of the hammer, especially the hammerhead.

The hammerhead is covered with a layer (or two) of felt. This felt has a particular density, a particular shape, and more importantly, a great deal of surface tension across its face, which is what makes the hammerhead bounce so smartly off the string. The technician can change these characteristics, changing the tone significantly. Most of these changes cannot be undone, however, so the technician must be quite careful. A full voicing of the piano aims for a smooth and consistent progression of tone over the entire range of strings.
Wippen: The wippen is a hinged lever that transfers mechanical advantage from the key to the hammer. The wippen holds the jack, and in grand actions it also holds a spring-loaded repetition lever. In upright actions, it holds the backcheck.